Choose your yard tree carefully: Problems may emerge years later

A tree planted in the wrong place may not reveal its problems for years. Its roots can damage foundations and paving, while its expanding canopy can deprive nearby plants of sunlight and water.

An analysis by a US environmental agency that combined the findings of 308 studies found that urban areas with green vegetation were, on average, about 1.6°C cooler than areas without it. In a private yard, however, shade does not necessarily mean more moisture. Large trees use substantial amounts of water, and during drought their roots can compete with nearby plants and weaken them.

Trees close to a house can still offer practical benefits. Deciduous trees shade walls and windows from summer heat, then allow sunlight into the home after losing their leaves in winter. The strongest cooling effect comes when shade falls on the southern and western sides of a building.

Before planting, gardeners should calculate the distance to walls, fences, paths and overhead power lines. They should also consider the position of vegetable beds, fruit trees, berry bushes and sun-loving flowers. Summer and winter shadows can differ greatly, so a tree that shades a terrace in June may later block light needed by other plants.

The article highlights red maple, or Acer rubrum, a deciduous tree from eastern North America. It grows quickly, reaches about 12 to 18 metres and can develop a canopy 9 to 15 metres wide. It prefers sun or partial shade and fresh, moist, slightly acidic soil. Alkaline soil can interfere with nutrient uptake and cause chlorosis. Its dense, shallow roots may compete strongly with plants beneath the canopy and cause damage if the tree stands too close to paths or foundations.

Japanese ornamental cherry is chosen chiefly for its striking spring flowers. It should not automatically be treated as one of the fastest-growing shade trees.